This circuit is from a 1980s Motorola documentation. The circuit makes use of old components that can in some cases be exchanged for modern equivalents.
This is a general purpose pramplifier launched in Brazil by Philips in the years 70. The BC549 is...
This complementary-output amplifier can be used to source a good qualuty signal to high impedance...
Found a documentation for PC from 1992, this circuit is indicated for the English power grid of...